1. Field of the Invention
The invention relates to a non-rinse, isotropic hard surface cleaner especially adapted to be used on glossy or smooth, hard surfaces, such as glass windows and the like, which removes soils deposited thereon, while significantly reducing the amount of residue caused by unremoved soil, cleaner, or a combination thereof. The inventive cleaner advantageously delivers an auditory xe2x80x9ccleanxe2x80x9d signal, the sound of a wicking implement, such as a cleaning cloth or sponge, squeaking or squealing when the cleaner is removed therewith from a smooth, glossy surface, such as a glass or mirrored surface.
2. Brief Statement of the Related Art
Cleaning hard, glossy surfaces such as glass windows has proven to be problematic. To remove soils deposited on such surfaces, the typical approach is to use an alkaline ammonium-based aqueous cleaner or other aqueous cleaners containing various mixtures of surfactants and other cleaning additives. Unfortunately, many of the ammonia-based cleaners have fairly poor soil removing ability, while many of the surfactant-based cleaners leave fairly significant amounts of residue on such hard, glossy surfaces. This residue is seen in the phenomena of streaking, in which the soil, cleaner, or both are inconsistently wicked off the surface, and filming, in which a thin layer of the residue actually clings to the surface desired to be cleaned.
Baker et al., U.S. Pat. No. 4,690,779, demonstrated a hard surface cleaner having improved non-streaking/filming properties in which a combination of low molecular weight polymer (e.g., polyethylene glycol) and certain surfactants were combined.
Church, U.S. Pat. Nos. 4,213,873 and 4,315,828, disclose hard surface cleaners containing water, a cleaning agent (ammonium hydroxide or an alcohol), and a lubricity agent, which is typically a polymer, but allegedly can include a mixture of ammonium carbonate and ammonium carbamate.
Corn et al., E.P. 0393772 and E.P. 0428816, describe hard surface cleaners containing anionic surfactants with ammonium counterions, and additional adjuncts.
G.B. 2,160,887 describes a cleaning system in which a combination of nonionic and anionic surfactants (including an alkanolamine salt alkyl sulfate) is contended to enhance cleaning efficacy.
WO 91/11505 describes a glass cleaner containing a zwitterionic surfactant, monoethanolamine and/or beta-aminoalkanols as solvents/buffers for assertedly improving cleaning and reducing filming spotting.
Garabedian et al., U.S. Pat. Nos. 5,252,245, 5,437,807, 5,468,423 and 5,523,024, and Choy et al., U.S. Pat. No. 5,585,342, all of common assignment herewith, disclose improved glass and surface cleaners which combine either amphoteric or nonionic surfactants with solvents and effective buffers to provide excellent streaking/filming characteristics on glass and other smooth, glossy surfaces. These disclosures are incorporated herein by reference thereto.
The invention provides an aqueous, hard surface cleaner with significantly improved residue removal and substantially reduced filming/streaking, said cleaner comprising:
(a) an effective amount of at least one organic solvent with a vapor pressure of at least 0.001 mm Hg at 25xc2x0 C., and mixtures of such solvents;
(b) an effective amount of a mixture of anionic surfactants;
(c) an effective amount of a buffering system which comprises a nitrogenous buffer which will result in a pH of greater than 6.5; and
(d) the remainder as substantially all water.
The invention provides an all-temperature, improved glass and other hard surface cleaner having excellent streaking/filming performance as compared to the prior art. The improvement is especially striking when cleaning glass and other glossy, hard surfaces with the invention.
In another embodiment of the invention, the cleaner further comprises (e) an effective amount of an additional dispersant, namely, an n-alkylpyrrolidone. This particular adjunct has proven to be surprisingly effective at both dispersing highly insoluble organic materials, particularly, fragrance oils, while simultaneously enhancing or maintaining the effective minimization of streaking/filming of the surfaces cleaned with the inventive cleaner.
The invention further comprises a method of cleaning soils from hard surfaces by applying said inventive cleaner to said soil (such as by, e.g., using a pump or trigger sprayer to conveniently and effectively deliver metered amounts of the cleaner to the soiled surface), and removing both from said surface.
It is therefore an object of this invention to substantially eliminate filming which results from a residue of cleaner, soil, or both remaining on the hard surface intended to be cleaned.
It is another object of this invention to substantially eliminate streaking, which results from inconsistent removal of the cleaner, soil, or both, from the hard surface intended to be cleaned.
It is also an object of this invention to provide a cleaner for glass and other hard, glossy surfaces, which has virtually no filming or streaking.
The invention is an improved cleaning, substantially non-streaking/filming hard surface cleaner especially adapted to be used on glossy or smooth, hard surfaces, emblematic of which is glass. The cleaner benefits from the use of a novel surfactant which contributes unexpectedly to the complete removal of soils and the cleaner from the surface being cleaned. The cleaner itself has the following ingredients:
(a) an effective amount of at least one organic solvent with a vapor pressure of at least 0.001 mm Hg at 25xc2x0 C., and mixtures of such solvents;
(b) an effective amount of a mixture of anionic surfactants;
(c) an effective amount of a buffering system which comprises a nitrogenous buffer which will result in a pH of greater than 6.5; and
(d) the remainder as substantially all water.
Additional adjuncts in small amounts such as fragrance, dye and the like can be included to provide desirable attributes of such adjuncts. In a further embodiment of the invention, especially when a fragrance is used, a further adjunct (e) a 1-alkyl-2-pyrrolidone is added in amounts effective, along with the anionic surfactant, to disperse the fragrance and to improve or maintain the reduced streaking/filming performance of the inventive cleaner.
In the application, effective amounts are generally those amounts listed as the ranges or levels of ingredients in the descriptions which follow hereto. Unless otherwise stated, amounts listed in percentage (xe2x80x9c%""sxe2x80x9d) are in weight percent of the composition, unless otherwise noted.
1. Solvents
The solvents useful in this invention are organic solvents with a vapor pressure of at least 0.001 mm Hg at 25xc2x0 C. and soluble to the extent of at least 1 g/100 ml water. The upper limit of vapor pressure appears to be about 100 mm Hg at 25xc2x0 C. Vapor pressure is a useful measure for determining the applicability of the given solvent, since one would select a solvent which will volatilize sufficiently so as to leave no visible residue. The organic solvent of the invention is preferably selected from C1-6 alkanol, C3-24 alkylene glycol ether, and mixtures thereof. However, other, less water soluble or dispersible organic solvents may also be utilized. It is preferred that a mixture of the C1-6 alkanol and C3-24 alkylene glycol ether solvents be used. The alkanol can be selected from methanol, ethanol, n-propanol, isopropanol, butanol, pentanol, hexanol, their various positional isomers, and mixtures of the foregoing. In the invention, it has been found most preferable to use isopropanol, usually in conjunction with a glycol ether. It may also be possible to utilize in addition to, or in place of, said alkanols, the diols such as methylene, ethylene, propylene and butylene glycols, and mixtures thereof. Other solvents, such as ketones, ethers, hydrocarbons and halides may be used. Other examples of solvents can be found in Kirk-Othmer, Encyclopedia of Chemical Technology 3rd, Vol. 21, pp. 377-401 (1983), incorporated by reference herein.
The alkylene glycol ether solvents can include ethylene glycol monobutyl ether, ethylene glycol monopropyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and mixtures thereof. One particularly preferred glycol ether is ethylene glycol, monobutyl ether, also known as 2-butoxyethanol, sold as Dowanol EB from Dow Chemical, while another commercially available one is Butyl Cellosolve by Union Carbide. The use of these particular glycol ethers in the invention results in a very low to minimal foaming cleaner, both upon application (spraying) and removal from (wiping) a hard surface. Another preferred alkylene glycol ether is propylene glycol, t-butyl ether, which is commercially sold as Arcosolve PTB, by Arco Chemical Co. If mixtures of solvents are used, the amounts and ratios of such solvents used are important to determine the optimum cleaning and streak/film performances of the inventive cleaner. It is preferred to limit the total amount of solvent to no more than 50%, more preferably no more than 25%, and most preferably, no more than 15%, of the cleaner. However, in some of the compositions of this invention, no solvent may be present. A preferred range is about 1-15%, and if a mixed solvent system of alkanol/glycol ether is used, the ratio of alkanol to alkylene glycol ether should be about 1:20 to 20:1, more preferably about 1:10 to 10:1 and most preferably about 1:5 to 5:1.
As mentioned above, other, less water soluble or dispersible organic solvents may also be utilizable herein, although in a high water formulation, there may be a need for a further dispersant (e.g., hydrotrope or other emulsifier). These less water soluble or dispersible organic solvents include those commonly used as constituents for proprietary fragrance blends, such as terpene derivatives. The terpene derivatives herein include terpene hydrocarbons with a functional group. Effective terpenes with a functional group include, but are not limited to, alcohols, ethers, esters, aldehydes and ketones.
Representative examples for each of the above classes of terpenes with functional groups include but are not limited to the following: Terpene alcohols, including, for example, verbenol, transpinocarveol, cis-2-pinanol, nopol, iso-borneol, carbeol, piperitol, thymol, xcex1-terpineol, terpinen-4-ol, menthol, 1,8-terpin, dihydro-terpineol, nerol, geraniol, linalool, citronellol, hydroxycitronellol, 3,7-dimethyl octanol, dihydro-myrcenol, tetrahydro-alloocimenol and perillalcohol; Terpene ethers and esters, including, for example, 1,8-cineole, 1,4-cineole, isobornyl methylether, rose pyran, xcex1-terpinyl methyl ether, menthofuran, trans-anethole, methyl chavicol, allocimene diepoxide, limonene mono-epoxide, iso-bornyl acetate, nopyl acetate, xcex1-terpinyl acetate, linalyl acetate, geranyl acetate, citronellyl acetate, dihydro-terpinyl acetate and neryl acetate; Terpene aldehydes and ketones, including, for example, myrtenal, campholenic aldehyde, perillaldehyde, citronellal, citral, hydroxy citronellal, camphor, verbenone, carvenone, dihyro-carvone, carvone, piperitone, menthone, geranyl acetone, pseudo-ionone, xcex1-ionone, xcex2-ionone, iso-pseudo-methyl ionone, normal-pseudo-methyl ionone, iso-methyl ionone and normal-methyl ionone.
Terpene hydrocarbons with functional groups which appear suitable for use in the present invention are discussed in substantially greater detail by Simonsen and Ross, The Terpenes, Volumes I-V, Cambridge University Press, 2nd Ed., 1947 (incorporated herein by reference thereto). See also, the commonly assigned U.S. Pat. No. 5,279,758, of Choy, incorporated herein by reference thereto.
2. Surfactants
The principal surfactants used in the inventive hard surface cleaner are anionic surfactants, for both cleaning and desirable foaming characteristics. The anionic surfactant is selected from alkyl sulfates, primary and secondary alkane sulfonates, alkyl diphenyl oxide disulfonates, alkylbenzene sulfonates, alkylsulfonates, isothionates, alkylethersulfates, xcex1-olefin sulfonates, alkyl taurates, alkyl sarcosinates and the like. Each of these surfactants is generally available as the alkali metal, alkaline earth and ammonium salts thereof. These surfactants can include both straight and branched alkyl chains, or mixtures thereof. The preferred anionic surfactants are alkyl sulfatesxe2x80x94more preferably, C6-16 alkyl sulfatesxe2x80x94alkane sulfonates and alkyl diphenyl oxide disulfonates. One particularly preferred sulfate is sodium lauryl (C12) sulfate, available from Stepan Chemical Co., under the brand name Stepanol WAC. A preferred alkane sulfonate is Bio-Terge PAS 8S, which is an octane sulfonate. In general, the C6-16 alkane sulfonates are preferred. Other manufacturers of alkane sulfonates include Hoechst AG, under the brand Hostapur. The alkyl diphenyl oxide disulfonates are atypical surfactants and preferably include an alkyl chain group of C6-20. The preferred alkyl diphenyl oxide disulfonates are from Dow under the brand name Dowfax. Especially preferred is Dowfax 3B2, an n-decyl diphenyloxide disulfonate. Pilot Chemical, with Calfax, is another source of the alkyl diphenyl oxide disulfonate surfactant.
In the invention, it was determined that the alkyl diphenyl oxide disulfonates are especially preferred. In addition to their improvement to cleaning performance, these surfactants enhance the inventive cleaners with the advantageous characteristic of an auditory signal when a hard surface is cleaned therewith. Specifically, when a cleaner formulated with said alkyl diphenyl oxide disulfonates is applied to a glossy hard surface, preferably glass or mirrored surfaces, and is then removed therefrom with the aid of a squeegee or wicking instrument, such as a cleaning cloth, sponge, or the like, a distinct xe2x80x9csqueakxe2x80x9d or squeal is heard, which signals the user that complete removal of the cleaner, and the soil, has been accomplished.
Further, a particular blend of anionic surfactants in this invention, alkane sulfonates, alkyl sulfates and alkyl diphenyl oxide disulfonates, is preferred because of the advantageous properties of imparting to the cleaner good physical stability, excellent streaking/filming performance, low to minimal foaming and the auditory xe2x80x9ccleanxe2x80x9d signal.
The amounts of surfactants present are to be somewhat minimized, for purposes of cost-savings and to generally restrict the dissolved actives which could contribute to leaving behind residues when the cleaner is applied to a surface. In a preferred composition, the total amount of surfactant is present, in a range of about 0.001-10%, more preferably about 0.001-7.5%, and most preferably about 0.001-3%, total surfactant. In the typical hard surface cleaners of this invention, and where a mixture of anionic/alkylpyrrolidone is used, the amounts added are generally about 0.001-2%, more preferably 0.002-0.75% anionic surfactant and generally 0.005-2%, more preferably 0.01-1% alkylpyrrolidone surfactant, in the cleaner, although it is again most preferred execution of the invention, the total amount of surfactant should not exceed about 1%. The ratios of surfactants are generally about 1:1,000 to 1,000:1.
3. Alkylpyrrolidones
The 1-alkyl-2-pyrrolidones can provide a dual function in this invention. First, one of the desirable adjuncts which are added to this system are fragrances, which are typically water-immiscible to slightly water-soluble oils. In order to keep this fairly immiscible component in solution, a co-solvent or other dispersing means was necessary. It was determined that 1-alkyl-2-pyrrolidones were particularly effective at so solubilizing the fragrance oils. The compound has the general structure: 
wherein R4 is a C6-20 alkyl, or R5NHCOR6, and R5 is C1-6 alkyl and R6 is C6-20 A particularly preferred alkyl pyrrolidone is lauryl (or n-dodecyl) pyrrolidone, sold by ISF Chemicals under the brand name Surfadone, such as Surfadone LP-300. Relatively low amounts of the alkyl pyrrolidone are used, preferably, about 0.001-2%, when the level of fragrance is from about 0.01-5%.
4. Buffer System
The buffer system comprises a nitrogenous buffer which is added to the aqueous hard surface cleaners of the invention so as to result in a pH of greater than 6.5, more preferably, between 7 and 14, most preferably between 7 and 13. The buffer can be selected from the group consisting of: ammonium or alkaline earth carbamates, ammonium carbonate, ammonium bicarbonate, diammonium carbonate, ammonium hydroxide, ammonia (which forms ammonium hydroxide in situ when added to water) and mixtures thereof. Optionally and preferably, the co-buffer is selected from ammonium and alkaline earth metal hydroxides. A combination of ammonium carbamate and ammonium hydroxide is most preferred.
The nitrogenous buffer is a significant aspect of the invention. Because of its presence, greatly enhanced reduction in streaking and filming of hard surfaces is achieved after the inventive cleaner is used to clean the same. The preferred nitrogenous buffers are ammonium carbamate, ammonium bicarbonate, ammonium carbonate and ammonium hydroxide. Ammonium carbamate has the structure NH2COOxe2x88x92NH+4. Use of this particularly preferred buffer obtains outstanding reduction in filming/streaking. It is available from BASF Corp. Ammonium carbonate and bicarbonate are other, further desirable buffers. Mixtures of any of the foregoing can be used as the buffer in the buffering system. Most of these materials can be obtained from general chemical supply houses, e.g., Aldrich Chemicals.
Additionally, it is especially preferred to add, as a co-buffer, an ammonium or alkaline earth hydroxide. Most preferred is ammonium hydroxide, which volatilizes relatively easily after being applied, resulting in minimal residue. Ammonium hydroxide also emulsifies fatty soils to a certain extent.
The amount of nitrogenous buffer added should be in the range of 0.01-2%, more preferably 0.01-1%, by weight of the cleaner, while hydroxide, if present, should be added in the range of 0.001-1% by weight of the cleaner.
5. Water and Miscellaneous
Since the cleaner is an aqueous cleaner with relatively low levels of actives, the principal ingredient is water, which should be present at a level of at least about 50%, more preferably at least about 80%, and most preferably, at least about 90%. Deionized water is most preferred.
Small amounts of adjuncts can be added for improving cleaning performance or aesthetic qualities of the cleaner. Adjuncts for cleaning include additional surfactants, such as those described in Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd Ed., Volume 22, pp. 332-432 (Marcel-Dekker, 1983), which are incorporated herein by reference. Inorganic builders, such as silicates and phosphates, are generally avoided in this cleaner, especially those which will contribute a large amount of solids in the formulation which may leave a residue. Aesthetic adjuncts include fragrances, such as those available from Givaudan-Roure, Belmay, Bush Booke and Allen, Henkel KGaA, Firmenich, Dragoco, IFF, Quest and others, and dyes and pigments which can be solubilized or suspended in the formulation, such as diaminoanthraquinones. The choice of color is left to the formulator, although various shades and hues of yellow, purple, green and blue, as well as colorless, are preferred. As mentioned above, the fragrance oils typically require a dispersant, which role is fulfilled by the alkylpyrrolidone, and the anionic surfactant. As previously noted, a fragrance is well dispersed by the alkylpyrrolidone while at least maintaining, if not improving, the non-streaking/non-filming performance of the inventive cleaner. The amounts of these cleaning and aesthetic adjuncts should be in the range of 0-2%, more preferably 0-1%.
An additional adjunct of interest herein is hydrotropes, specifically, short chain alkylaryl sulfonates, more specifically, C1-4 alkylaryl sulfonates, such as, without limitation, benzene, naphthalene, xylene, cumene and toluene sulfonates. These are typically alkali metal salts and, although it has been cautioned herein that the total level of alkali metal salts is to be limited, in fact, for certain purposes, such as hard surface cleaning (e.g., tile, composite materials such as Formica(copyright) and Corian(copyright) countertops, and the like), incorporation of hydrotropes in a discrete level may be quite acceptable. The preferred hydrotrope herein is alkali metal xylene sulfonate, wherein the alkali metal is potassium, sodium or lithium. An ammonium salt may also be acceptable. The amount of short chain alkylaryl sulfonate may be kept economically low, i.e., preferably about 0.01-2%, more preferably 0.02-1% and most preferably, about 0.05-1%. Preferred hydrotropes, among others, include sodium xylene sulfonate, sold in various active levels by Stepan Chemical Company under the brand name Stepanate SXS. Other preferred hydrotropes may be found from Colborn et al., U.S. Pat. No. 4,863,633, column 8, line 20 to column 10, line 22, which are incorporated by reference thereto.
In the following Experimental section, the surprising performance benefits of the various aspects of the inventive cleaner are demonstrated.
The following experiments demonstrate the unique cleaning performance of the inventive cleaner.